Milton CAT 772 - Manual (Page 7)

New A-Frame. The new A-frame mounts
directly to the spindles. The new A-frame
eliminates the “king” bolt and includes a
pin and bushing style mounting, consistent
with the 777 and 793. This new design
is simpler to maintain and service.
New Ductile Iron Spindles. A stress-
optimized, ductile iron spindle is
splined to the rear brakes, reducing
brake pack rebuild time by up to two
hours. In addition, the spindles are
longer and wider with fewer seals
for increased strength and durability.
Brake Packs. A single-piece brake anchor
eliminates more than 200 fasteners and
a row of bolted joints. Rebuild time is
reduced by up to two hours. In addition,
the brake pack is removable without
taking the spindle off the truck.
Each of the two oil-cooled disc brakes
on the 772 rear axle features 30 discs.
The brake discs have increased in
diameter from 495.3 to 540.0 mm
(19.5 to 21.3 in). By increasing the
diameter, Caterpillar has improved the
overall reliability and durability of the
brake packs and has also designed the
brake packs to improve the OD/ID ratio.
The new 772 brake pack design, moves
the braking forces to the outer edge of
the disc, thereby using greater surface
area for improved braking forces and
longer life, improving reliability and
lowering maintenance cost.
Wheel Stations. The wheel stations now
integrate both the wheel and the hub.
The single-piece design reduces removal
and installation time, and the risk of
brake cooling oil leakage. The inner
Duo-Cone™ seal has been changed
from a formed type to a cast design.
Brake cooling flow and the Duo-Cone
seal has also been reversed for better
sealing performance and improved
seal life.
Wheel stations are now interchangeable,
reducing the number of replacement
parts: left and right wheel stations are
symmetric and can be interchanged.
In addition, the new design eliminates one
o-ring seal, which improves reliability
and simplifies the system and the wheel
bearings have been enhanced for longer
bearing life.
Tires. The 772 uses larger 21.00R33 tires.
The larger tires increase the load carrying
capacity of the machine, which is
needed for the increased target payload
of 45 tonnes (50 tons). The new 772
lowers the cost-per-ton by optimizing
the tire size to GVW ratio.
• Steering System. Hydraulic steering
control system is designed for
exceptional smoothness and precise
control. A separate circuit prevents
cross contamination for long life.
• Battery Powered Supplemental
Steering. A battery powered
supplemental steering system uses
pressure accumulators and allows
up to three 90 degree turns in case
of engine failure.
• Wheels and Rims. Cast rear wheels and
Cat center-mount rims are mounted using
studs and nuts to minimize maintenance
and maximize durability.
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